Given the U.S. Energy Information Administration's projection that shale gas consumption will increase by over 450% by 2025, the drawbacks of existing separation methods will become only more harmful. Existing technologies for gas separations (i.e., fractional distillation) are cost- and energy-intensive and pose risks to the environment. Additionally, distillation units must often be tailor-designed for specific feedstocks to operate efficiently, but because gas composition can vary dramatically based on the geographical location of the deposit, large-scale implementation of distillation can be difficult. Removal of the acid gas impurities present in crude natural gas—such as carbon dioxide and hydrogen sulfide—remains a further challenge, as these impurities cause equipment corrosion and pose a human health risk.
Membrane separations have found increased use in industrial applications as an alternative approach where conventional separation techniques fall short. Membrane units also possess the ability to accomplish separations traditionally difficult for distillation, such as breaking azeotropes. But there is a well-known tradeoff between the permeability and selectivity of membranes due to their sieving effects, which tradeoff is shown by the well-known “Robeson plot.” Advances in materials design have led to an upward shift in this upper bound, but there is still a long-felt need in the art for improved separation materials and methods, particularly for technologies that address the tradeoff between permeability and selectivity.
Current polymeric membranes for liquid and vapor separations suffer from various limitations. First, such membranes have a relatively short lifespan before they require replacement or reprocessing, after which reprocessing their effectiveness may be reduced. Second, existing membranes vary in quality and performance, meaning that two membranes produced in a similar way may not exhibit similar performance in the field. Accordingly, there is a long-felt need in the art for improved fluid separation materials and related methods.